Aggression Summary

Observation:

• Learning takes place through the observation of role models
• Seeing other reinforced or punished acts as vicarious reinforcement

Mental Representation:

• Individual forms mental representations of events
• Also forms expectations of possible rewards or punishments

Production of Behaviour:

• Aggression maintained through direct reinforcement
• Likelihood of aggression increased if high self-efficacy for production

Bobo Doll Studies:

• SLT demonstrated in young children observing aggressive adult model
• Imitated model, but only if model was rewarded for their behaviour

Evaluation:

• Learning takes place regardless of outcome, but production linked only to reinforcement
• SLT also applies to aggression in adults
• Can explain aggression in absence of direct reinforcement
• Also explain individual differences and context-dependent learning

IDA:

• Cultural differences - absence of aggressive models among !Kung San
• Problem of demand characteristics in Bobo doll study

Nature of Deindividuation:

• Reduce self-evaluation; decreased concern about evaluation by others
• Leads to an increase in antisocial behaviour
• More likely when anonymous in a large crowd

Process of Deindividuation:

• Social norms usually inhibit antisocial behaviour
• Inhibitions removed when deindividuated
• Conditions that increase anonymity weaken barrier to antisocial behaviour

Research on Deindividuation:

• Anonymity - Zimbardo (1969) found longer shocks when anonymous
• Faceless crowd - lynchings more savagve when large crowds (Mullen, 1986)
• Baiting crowd (Mann, 1981)

Reduce self-awareness:

• Reduced self-awareness more important than anonymity
• In large crowds, less able to self-regulate behaviour

Evaluation:

• Local group norms - people respond to normative cues within the social context
• Meta-analysis (Postmes and Spears, 1988) found insufficient support for many claims of deindividuation theory
• Deindividuation may increase prosocial behaviour in some situations

IDA:

• Gender difference - males more likely to become aggressive when deindividuated
• Cultural difference - cultures that change appearance more brutal in war

Within groups:

• Importation model - prisoners bring violent behaviours with them
• Deprivation model - a reaction to stressful conditions of prison
• Hazing - institutional bullying based on initiation into group
• Product of situational forces and cultural notions of 'male' behaviour and toughness

Evaluation:

• Importation model - some support studies of US prisoners
• Deprivation model - support from prison studies but not institutions
• Hazing - research support among inmates in prisons

Between Groups:

• Staub (1999) - five stages in process of genocide
• Dehumanisation - removal of moral restraints against killing other humans (Tutsi)
• Obedience - Milgram believed situational pressures could coerce people into destructive obedience

Evaluation:

• Bystanders - non-intervention allows killing to continue
• Dehumanisation - may explain violence against immigration
• Obedience - ignores other factors (e.g antisemitism)

IDA:

• Dehumanisation is difficult to investigate empirically
• Ethical issues in studying people who have been subjected to dehumanising violence

Neurotransmitters:

• Low levels of serotonin and high levels of dopamine asociated with aggression
• Serotonin normally inhibits responses to emotional stimuli that might lead to an aggressive response
• Mann (1990) - dexfenfluramine deplete serotonin in brain, and led to an increased aggression in males but not in females
• Amphetamines increase dopamine activity - also increase aggressive behaviour
• Antipsychotics reduce dopamine activity - also reduce aggressive behaviour

Neurotransmitter Evaluation:

• Meta-analysis (Scerbo and Raine, 1993) found evidence for serotonin-aggression link, but not dopamine-aggression link
• Animal studies suggest lower levels of serotonin associated with aggression and dominance
• Research support from antidepressants that raise serotonin levels
• Dopamine may be a consequence rather than a cause of aggression

Hormonal Mechanisms:

• Meta-analysis have established weak but positive correlation between testosterone and aggression (Archer 1991; Book et al, 2001)
• Dabbs et al (1987) - testosterone levels high among violent criminals
• Challenge hypothesis - testosterone levels rise in response to social challenges
• Cortisol - high levels inhibit testosterone and so inhibit aggression

Hormonal Mechanisms Evaluation:

• Inconsistent evidence for testosterone-aggression link
• Influence of testosterone linked to dominance rather than aggression (Mazur, 1985)
• Cortisol - link supported by study of boys with behavioural problems

IDA:

• Reductionism - human social behaviour more complex, therefore biological factors represent an incomplete picture
• Gender bias - research tends to focus on males, but studies of females also show important role for testosterone

Twin Studies:

• MZ twins genetically identical, more similar levels of aggressive behaviour than DZ twins indicates genetic influence
• Coccaro et al (1997) - genetic factors account for 50% of variance in aggressive behaviour

Adoption Studies:

• Possible to disentangle genetic and environmental factors by comparing adopted children and biological parents
• Hutchings and Mednick (1975) - children with criminal convictions had fathers with criminal convictions

Gene for aggression:

• Gene for MAOA associated with aggression
• MAOA regulates serotonin in brain, low levels of serotonin associated with aggression
• Brunner et al (1993) - violent men in Dutch family had abnormally low levels of MAOA

Genetics and Violent Crime:

• Inherited temperament or personality characteristics place some individuals at risk of committing violent crime
• Brennan (1993) - genetic influences significant in property crime but not violent crime

Evaluation:

• Difficult to determine what is a product of genetic inheritance
• More than one gene contributes, as do environmental factors, and there is an interaction between the two
• Problems of measuring aggression
• Individual differences in aggression due to environmental rather than genetic influences
• Studies of youth violence do not suggest a strong role for heredity

IDA:

• Problems of sampling - violent criminals represent small minority of people involved in aggression
• Some violent criminals are not generally 'aggressive'
• Animal studies
• Possibility of genetic engineering creates ethical issues

Infidelity and Jealousy:

• Men experience sexual jealousy because of the threat of cuckoldry
• Sexual jealousy designed to deter a mate from infidelity
• Males have evolved mate retention strategies
• Wilson et al (1995) - women whose partners were sexually jealous more likely to have experience violence from them
• Uxoricide - wife-killing may be unintended outcome of adaptation to control mate

Evaluation:

• Use of mate retention strategies and female-directed violence supports by research (Shacklford et al, 2005)
• Application - use of mate retention strategies is early indication of the need for intervention
• Uxoricide - alternative explanation by Duntely and Buss (2005), killing wife prevents competitor gaining in reproductive stakes

IDA:

• Limitations of survey data
• Most research focused on mate retention stategies by males even though many assaults are by wome

Lynch Mobs:

• Lynchings due to 'fear of the *****' during periods of social transition
• Power-threat hypothesis - groups that pose threat to majority more likely to be discriminated against

Evaluation:

• Boyd and Richerson (1990) - research support; groups in which cooperation thrived were those that flurished
• Clark (2006) - evidence from lynchings in Brazil contradicts idea of 'dangerous classes'

Religious Rituals:

• Costly signalling theory - the costs associated with religious rituals signal commitment to a group
• Zahavi (1997) - significant costs act as a deterrent for those who do not accept religion but seek advantages of group membership 

Evaluation:

• Religions requiring the greatest displays of commitment last the longest
• Costs of rituals should be related to incentives of group membership

Sport events:

• Xenophobia - suspicion about strangers, adaptive as helps avoid attack
• Demonstrated in xenophobic responses of Italian football crowds
• Xenophobia more evident with national sides rather than club sides

Evaluation:

• Research support - Foldesti (1996) found link between xenophobic outbursts and crowd violence among Hungarian football crowds
• Marsh (1978) - alternative explanation, football violence as a career

IDA:

• Lynch mob behaviour can also be explained in terms of deindividuation
• Evolutionary approach - increased intra-group solidarity may lead to increased inter-group conflict